Electric telegraphy.



0. IVIOLL 6L P. KUSCHEWITZ.

ELECTRIC TELEGBAPHY.

APPLICATION FILED APR. 25| I9I4-.

Imm.. Patented Feb. 26,1918.

2 SHEETS-SHEET I.

O. [I/IOLL L P. KUSCHEWITZ.

ELECTRIC TELEGRAPHY.

APPLICATION FILED APR. 25. 1914.

Patented; IFIIb. 26,1918.

2 SHEETS-SHEET 2.

OSKAR MOLL ANDV PAUL KUSCI-IEWITZ, OF VBL.AC'Kl-lEl'IIII-I, ENGLAND.

ELECTRIC TELEGRAPHY.

restais.

Specification of Letters Patent.

Patented Feb. 26, i918.

Application iled April 25, 1914. Serial No. 834,478.

T 0 all whom t may concern:

Be it known that we, OsKAR MoLL, a subject of the King of Great Britain, and PAUL KUsCHnwrrz, a subject of the King of Prussia, both residing in Blackheath, lingland, and whose post-ofhce address is 75 Charlton road, Blackheath, in the county of Kent, England, have jointly invented certain new and useful Electric Telegraphy, of which the following is a specification.

in the specification of our United States Patent Application, Serial No. 7 69,298, methods are described 'tor protecting telegraph and like wires against inductive action fromneighboring circuits, by theinsertion of primary coils or other protecting devices in the disturbing circuit. Since it is notalways possible or convenient to obtain access to the disturbing circuit tor this purpose, in the present invention means are devised by which these disturbances can be eliminated without any access to the said disturbing circuit. i The arrangements are more particularly suitable for submarine cables and are illustrated in the accompanying examples as applied to this purpose, but they are also adaptable to eliminate disturbing influences in telephone or other lines provided with sensitive receiving instruments.

lin the accompanying drawings, examples are shown diagrammatically of the circuit arrangements of a submarine cable adapted for duplex working. Figure 1 represents a usual known arrangement. Figs. 2 to 6 represent circuitv arrangements according to the present invention. Similarl parts are denoted by the same reference letters in all the figures. f

Iny order to protect submarine cables or other lines as far as possible from disturbing currents it is usual to lead the cable to a station in a district freefrom disturbance and then 'from this place, where the artificial cable required for duplex working can also be installed, to continue the circuit as a double line through the district in which the disturbing elements are present to the receiving station itself. Fig.l l shows a known arrangement of this kind, in which A is the receiving station, containing `the receiving instrument M, B the station to which the cable is led, a and Z) the double line between the stations A and B. T is a double current key for signaling from station B over the submarine cable. C, and C, are condensers inserted inthe working and artilicial cables, m and n the arms ot the bridge to which the key T is connected, K1 and K2 represent the working and artificial cables.

That this known arrangement does not eliminate all disturbances in the circuit of the double line, may be easily seen trom the following considerations:

The Ydisturbing current l produces currents z', and z', in the two branches a and b of the double line between A and B and voltages V1 and V2 at the terminals ot the receiving instrument M. The latter ca only be unaffected by the disturbing current, if the instantaneous values of the phase and intensity of the currents i, and 2 or of the voltages V1 and V2 produced by these'currents are'always the same. rthis assumes? that the double lines are both at the same mean distance from the disturbing currents and also that the capacity resistance and self inductance of the line t with the cable connected to it and the arm m of the bridge are exactly equal to the corresponding values of the line b with the artificial cable and the arm 'n of the bridge. But this would only be possible when the bridge was balanced with equal arms (mzn and 01:(32). A balance cannot in general be obtained with equal arms in the bridge and we therefore provide novel means which will prevent disturbances and at the Sametime allow the bridge arms to be adjusted as required.

Arrangements have been proposed by which a third conductor is carried through the disturbed district for the purpose of compensating electrostatic disturbances and is connected at the receiving instrument to a balancing capacity and resistance, but in the system according to the present invention, such third conductor is not required. It has also been proposed, where there is a` single line between Vthe receiving instruments at each end of a duplex cable installation to earth each side of the instruments over` a resistance and a capacity, which are adapted to compensate disturbing influences of givenl strength and frequency, but the known arrangement ditl'ers considerably from the method of the present invention by 'which such shunt circuits are avoided and in which the double line over thek disturbed district is rendered immume from disturbing influences of any strength or frequency.y

According tothe present invention, in one arrangement, in which the double line is `directly connected to the cable, means are Y a b at points m, y. One of'these resistances includes' a variable self inductance L, the other is shunted by a variable capacity. By the proper adjustment of these factors thel currents z', and 2'2 due toI the disturbing causes can be equalized both in phase and amplitude and the voltages V1, V2across the receiving instrument are thus made equal and the disturbances thereby eliminated.'

In Fig.l 3 the connections at station B are similar to those shown in Fig. 1, but instead of inserting resistances, inductances Vand capacities in the lines, a bridge is arranged across the receiving instrument at stationrA, whose arms Z1, Z2 are connected to points Z Z2 and to earth, such arms comprising adjustableresistances r1, R2, 1'2, R2, of which R, and R2 are shunted by variable'capacities C3 and C2. By suitably adjusting the arms Zlrand Z2, the voltages V1, V2 due to disturbing currents, which find their way into the lines a, t, canl be equalized. This arrangement allows, when suitably adjusted, of sending from station:

B without disturbing the receiving instrument.

l/Ve now proceed to describe means applicable to duplex working, whereby the. disturbances are eliminated and `at the same. time the'lines a, 6 can be used for sending fromv station B, sol that the special line from station lA for operating the4 sending relays,

at station B is eliminated.y .y Y

Referring to Fig. A, the bridge armsv at stationv .A are vsimilar to those shown in- Fig. 3, but their vertex is connected through key T to earth. When one of the keys is depressed a battery BS is included in this connection to earth, the polarity direction of the sending current depending in the well, known manner, on .which lever is depressed.`

station B t'hereis a corresponding eartl'iy connection t'o whichjare.V connected the coils of. two oppositely polarized'relays. A1,

ary 'of a transformer' which is connected directly across the lines a, b. The primary o'f the transformer consists of three coils P1, P2, P2, which are connected directly across the working and artiiicial cables at the points 101,102.

The action is as follows On depressing one of the levers of the key T, current fiows to the vertex of the bridge at A, flows through the leads a, b in parallel, and in opposite directions through the coils S1, S2 and through the conductor c, and the coils of the relays A1, A2 to earth, thereby operating either the relay A1 or the relay A2 according to the polarity of the current, that is according to which lever of the key T was depressed. The currents in the two windings S1, S2 of the secondary coil being equal and opposite there will be no inductive effect on the primary coils P P2, P3, and if thearms Z Z2 of the bridge at A are properly balanced, there will be no disturbance of the receiving instrument M. The relays A1, A2 send positive or negative currents respectively into the cables through the bridge arms m, n, in the usual manner. In this way sending can be effected without disturbing the receiving instrument and without an extra line for operating the relays, and at the same time disturbances of the instrument M due to extraneous causes are eliminated by suitable adjustment of the variables in the arms 2 Z2.

At the same time a further advantage is offered by these arrangements because by suitable adjustment of the capacities C2, 0 100 and the resistances R2, R2, arranged in parallel therewith,the relays A1, A2 can be made to respond sharply to the movements of the key T. Moreover the factthat the condensers C'3 and C2 are shunted by the 105 resistances R, and R2 insures that the discharge of these condensers shall take place through the resistances, instead of through the relay circuits.

The arrival currents from the cable iow- 110 ing into the artificial cable through the primary windings Pl, P2, P induce corresponding currents in the secondary winding S1, S2, thereby operating the receiving instrument The arms Z1,y Z2 form a shunt to the r'eceiving instrument M, but owing to their high resistance and the arrangement of the condensers C3, C4 in series for currents flowing in this path, very little current is shunted 120 from the receiving instrument M.

Fig. 5 shows certain modifications in and additions to the arrangements at station A; the resistances 13, r2 are replaced by the primary windings P5, PG of transformers, the 125 secondary windings. S5, S2 of which can be either connected across the receiving instrument M in series with the condenser C5y and a resistancefr4L arranged' in parallel, or can be short cire'uitedI by the switch shown. 13o

Currents flowing over the leads a, Z in parallel will have no inductive effect on these secondaries, but any current flowing through the arms of the bridge in series, such as will be produced by a diderence of potential at VU-Vg, will produce an inductive effect on the secondary windings S5, S6, which will tend to prevent the arrival current from taking the path through the shunt. The same effect is produced by short circuiting the windings S5, S6.

If the balance at station B is imperfect, an improvement can be effected in the balance of the system by a suitable variation of the arms of the bridge at A.

, Fig. 6 shows arrangements by which the advantages of Figs. 4 and 5 can be obtained and at the same time enable a Heurtley relay or other suitable instrument to be used for magnifying the received signals. As before, the secondaries S7, S8, corresponding to the secondaries S1, S2 in Fig. 4 are arranged in the form of a bridge whose ver- Y tex is at C and the corresponding primaries 1) l?8 are normally connected, as shown by the dotted lines, With the points w1, fw2 of the working and artificial cables respectively. Resstances R3, R, shunted by condensers C6, C7 may be inserted in series with the secondaries S1, S2. When it is desired to use a Heurtley magnifier or other similarapparatus, the primaries P1, P, are disconnected from the points w1, wz; and are short circuited upon themselves. The Heurtley coil H is thus connected across the points 10 wg; g1, g2, g3, g4t are the resistances in the bridge, of which g1, g2 are varied by the deflection of the coil H. B2 is the battery connected across one diagonal of the bridge, the other diagonal of which is connectedv across the line a, b at the points zr, y.

The operation of sending takes place as described with reference to Fig. 4; the sending current iowing to the relays A A2, through c S, and b S2 in parallel, produces no inductive effect on the primary windings P1, P2. Moreover, if the primaries P1, F2 are short circuited, as when the Heurtley relay is used, any tendency for the arrival current from the cable to flow through the lines S1, S2, which form a shunt to the re ceiving instrument is reduced.

If it is not desired to use the transformer action between the primary and secondary coils, S, and S', can be replaced by non-inductive resistances.

Having thus described the nature of the said invention and the best means We know of carrying the saine into practical effect, we claim :fi

1. Means for protecting duplex submarine cable systems, comprising a l/Vheatstone bridge having a receiving instrument in the diagonal thereof, variable resistances and variable capacities inparallel thereto in'the adjacent arms of the bridge, and other arms of the bridge constituting a double line connecting the receiving instrument with the distantly located shore end of the working cable and the articial cable.

2. Means for protecting duplex submarine cable systems, comprising a VVheatstone bridge having a receiving instrument in the diagonal thereof, variable resistances and variable capacities in parallel thereto included in the adjacent arms of the bridge, and other arms of the bridge constituting a double line connecting the receiving instrument with the distantly located shore end of the working cable and the artificial cable, over which double line the arrival currents are transmitted in series and the sending currents are transmitted in parallel.

3. Means for protecting duplex submarine cable systems, comprising a 1Wheatstone bridge having a receiving instrument inthe diagonal thereof, variable resistanees and variable capacities in parallel thereto included in the adjacent arms of the bridge, other arms of the bridge constituting a double line connecting the receiving instrument with the shore end of the working cable and the artificial cable` relavs operative by sending currents transmitted in parallel over the said double line, and a transformer having said relays connected to the junction of its secondary windings and having its primary windings connected to the working and artiicial cables.

4. Means for protecting duplex submarine cable systems, comprising a Wheatstone bridge having a receiving instrument in the diagonal thereof, variable resistances and variable capacities in parallel thereto included in the adjacent arms of the bridge, other arms of the bridge constituting a double line connecting the receiving instrument with the shore end ofthe working cable and the artificial cable and bridging the said double line at the cable end thereof, transformer windings connected in series with resistances, and capacities shunting the last-mentioned resistances.

5. Means for protecting duplex submarine cable systems, comprising a Nheatstone bridge having a receiving instrument in the diagonal thereof, variable resistances and variable capacities in parallel thereto included in the adjacent arms of the bridge, two arms of the bridge constituting a double line connecting the receiving instrument with the shore end of the working cable and the artificial cable, and transformer windings bridging the said double line so arranged that an inductive action occurs between the primary and secondary windings by the arrival but not by the sending currents.

6. Means for protecting duplex submarine cable systems, comprising a. Wheatstone lll@ bridge having a receiving instrument in the diagonal thereof, variable resistances and variableA capacitiesin parallel thereto included in the adjacent arms of the bridge, tpWo arms-of the bridge constituting a double line connecting the receiving instrument with the shore end of the working cable and the artiiicial cable, a transformer having its secondaryfwindings bridging the said double line at the cable end thereof, the primary windings of the transformer normally bridging the working and artificial cables and capable of being short-circuited when the said Working and articial cables are bridged by a senstive relay.

7. Means forprotecting a duplex submarinecable system,comprising a Wheatstone bridgehaving a receiving-instrument in the diagonal thereof, resistances included in theadjacent arms of the, bridge in parallel With` variable capacities, coils also included in said; arms, and secondary windings acted om i'nd'uctivelyA by said coils, said secondary windingsbridging'the. terminals of theA said receiving instrument. Y Y

V8: Means for protectingv a d upleX submarinev cable system, comprising a Wheatstone bridge, having a1receivinginstrument in the diagonal thereof, resistances included in the adjacent; armsA of the bridge in parallelY withy vari-able; capacities, coils also, included in said arms of the'bridgc, and secondary windings acted on rndlvltivelybyv said coils manera and connected overa capacity, shunted b v a resistance, with the terminals of the receiving instrument.

9. Means for protecting duplex submarine cable systems, comprising a Wheatstone bridge having a receiving instrument in the diagonal thereof, variable resistances ineluded in the adjacent arms of the bridge, variable capacities in parallel with said resistances, two arms of the bridge constitut ing a double line connecting the receiving instrument with the shore end of the working cable and the artificial cable, transformer windings bridging the said double line, so arranged that an inductive action occurs between the primary and secondary windings by the arrival but not bythe send ing currents, and a switch for short-circuiting the said secondary windings on themselves when requiredl In testimony hereof we have signed our namestoy this specification in the presence of two subscribing witnesses.

OSKAR MOLL. PAUL KUSCHEWITZ.

Witnesses to thef signature of Oskar' Moll Wl L.,Ki\oRR, J os. EULER. Witnesses tol the signature of Paul Kuschewitz:

ERNEsrf KATZ', ERNEST H. BLEIST.

Copies oi this patent may be obtained for ve cents each, by addressing the Commissioner of Patents,

' Washington, D. C. 

